Lebanon was founded in 1756, originally named Steitztown. Lebanon was incorporated as a city in 1886 and is the seat of Lebanon County. The city lies in the Lebanon Valley east of Harrisburg.

Lebanon served as a supply depot and storehouse for ammunition during the occupancy of Philadelphia by the British during the American Revolutionary War. During the war the furnaces at nearby Cornwall supplied large quantities of iron for cannon and balls for the American army. At one time the Cornwall furnaces maintained most valuable and remarkable body of iron-ore in the world.

Lebanon County has a population of over 120,000 and is part of the Harrisburg metropolitan area.